Bell 525 Relentless Controls: ‘Just Grab It and Fly It’

By Ernie Stephens, Editor-at-Large

Bell engineers use the 525 Relentless simulator to test the ergonomics
and flight characteristics of the “super medium” helicopter design.
Note the side-stick configuration of the fly-by-wire controls.

Last year, Fort Worth, Texas-based Bell Helicopter unveiled the mock-up of its model 525 “Relentless,” the aircraft its designers call a “super medium” twin. Designed to carry up to 18 people in a dense seating configuration, the 10,000-to-11,000-lb. (empty weight) ship is being developed primarily with the offshore support market in mind.

To assist engineers with tweaking the 525’s handling characteristics and flight deck ergonomics, Bell built a concept simulator programmed to duplicate as many parameters as possible. The company then shipped the simulator to Heli-Expo 2013 in Las Vegas in early March for attendees to try. Rotor & Wing was one of the first to be invited aboard.

For the technical purist, Bell did not actually bring a “flight simulator,” which by most definitions is a machine that moves in order to give the feeling of flight. Instead, it was actually a “flight training device,” or FTD, a learning tool that is laid out like an actual aircraft, but has moving graphics instead of a moving platform. But for our purposes here, I’ll continue to call it a simulator.

Full view of the Bell 525 flight training device that
the company brought to Heli-Expo.

The 525 simulator is more of a technology and cockpit ergonomics concept demonstrator made to stay on the ground. Bell explains that a customer review panel meets regularly to discuss the progress of the aircraft’s design, and to use the simulator to test the outcomes. If anything disappoints the review panel, all efforts are made to correct the problem.

Consequently, sources say that the layout of the ARC Horizon and Garmin G-5000H touchscreen displays in the simulator have already been rearranged for aircraft #0001. But for now, the aircraft’s unique fly-by-wire (FBW) side-stick configuration for the cyclic and the collective are features that will reach the production model. And I can see why. With just a couple of quick and easy adjustments to the high-back seat and forearm rests, sitting in the real 525 will be like sitting in an easy chair.

If the flight model of the simulator is an accurate representation of how the actual aircraft will handle, the flying example of the Bell 525 will be as automated or as basic as the pilot wants at any given time. Hover position is held by GPS information, and can be tweaked by displacing the cyclic a half-inch in the desired direction, or with the cyclic-mounted hat switch. Transitioning to forward flight, performing altitude changes and making heading adjustments is a simple matter of moving the controls farther, or “beeping” the hat switches on the collective and cyclic with more authority. To let the aircraft capture and hold the new numbers, just let the controls go. In fact, if you want to manually manipulate one control, just grab it and fly it. The 525 will automatically relinquish it to you, and maintain the others as previously directed.

Garmin screens up close during a simulated Bell 525 flight.

For grins, I headed for an oil rig depicted about five miles dead ahead in the simulation. I made most of the approach to the pad by beeping in my heading, rate of descent, and rate of closure choices. I carried out my second approach without any automation just to find the 525’s manners to be equally impressive. If the simulator is any indication of how the real aircraft will fly, pilots of the Bell 525 Relentless will find a helicopter that is comfortable, user friendly, and willing to accept as much or as little hands-on control as is offered by the aviator. It should prove to be an interesting ship to drive.

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